Apparatus for molding or lining hollow articles



Nov. 16, 1943. R. B. REEVES APPARATUS FOR MOLDING OR LINING HOLLOW ARTICLES 7 Filed Oct. 20, 1941 4 Shee ts-Sheet 1 w m nd H 1 m M113. H4 n a lllll Nov. 16, 1943.

4 Sheets-Sheet 2 B. REEVES Filed o t. 20, 1941 APPARATUS FOR MOLDING OR LINING HOLLOW ARTICLES llHHl T0 ATM06'P/IERE 6, 3- R. B. REEVES APPARATUS FOR MOLDING OR LINING HOLLOW ARTICLES Filed Oct. 20, 1941 4 Sheets-Sheet s Patented Nov. 16, 1943 APPARATUS FOR MOIDING OB LINING HOLLOW ARTICLES Robert Bruce Reeves, Chelmaford, England Application October 20, 1941', Serial No. 415,802 In Great Britain October 28, 1940 7 claims. (01.25-30) This invention relates to apparatus for manufacturing hollow articles, for example pipes and ducts, from plastic materials, for example concrete, or lining hollow bodies, with such materials, of the type comprising a core having an extensible covering sleeve which is forced away from the core during the molding by means of fluid under pressure admitted between the core and the covering sleeve, so as to compress the plastic material in the mold or the article to be lined.

One object of the invention is to provide a simple and eflicientapparatus whereby articles 'are produced which have very dense and strong walls, and linings are formed which are very flrmly pressed against their supports.

Another-object oi the invention is to expedite the molding of the hollow articles and reduce the time during which the molded articles remain in the mold.

A further object of the invention is to facilitate the removal oi'the molded articles from the mold. Y

With these objects in view, the invention consists in the provision of an outer casing having a mold therein, comprising a plurality of longitudinal sections, said outer casing having guide rings thereon for preventing movement of the mold sections relatively to the outer casing in the axial direction but permitting movement of the mold sections in the radial direction, to enable the mold sections to be detached from the molded article after the molding has been completed, the core being provided on a base which supports the outer casing and the mold during the molding and the arrangement being such that the outer casing, together with the mold' containing the molded article, can be removed from said base after relaxation of the fluid pressure between the core and the covering sleeve. By this means, the molded article can be transferred to a separate support, and the mold casing containing the mold can then be returned to the base for the production of another molded article, after detachment and removal of the mold from the molded article.

Where the apparatus is used for the provisio of a lining in a hollow article, the latter is placed in the mold and the lining is formed between the hollow article and the core having the extensible covering sleeve.

Any desired plastic material may be used. Moreover, any form of reinforcement may be used in connection with the plastic material, for the purpose of obtaining additional strength,

e. g., in the case of articles made of concrete, metal rods or expanded metal may be embedded in the concrete. Also, any suitable extensible material, e. g., rubber, may be used for the ex- Figure 5 is a part vertical section through a v further modification.

Figure 6 is a part vertical section on the line 6-6 of Figure 7 of another modification, and

Figure '7 is a transverse section on the line 1-1 of Figure 6.

In the embodiment of the invention illustrated in Figures 1-3, for the purpose of making concrete pipes or ducts, use is made of a cylindrical core la surrounded by a sleeve 8 of extensible material, such as rubber. The'lower end of the core is formed as a pressure chamber 9, and is secured to a flanged base l0 having an inlet pipe ll through which fluid under pressure may be admitted to the interior of the end 9 of the core under the control of a valve V. The core has openings 52 through which the fluid has access to the interior of the sleeve 8.

The mold is cylindrical and is divided longitudinally into two sections l3a, lab, which are surrounded by an extensible sleeve H which fits tightly round them and holds them in position. The mold sections are supported in an outer casing ii, the lower end of which is supported on and detachably secured by dogs I" to the flange Inc of the base Ill. The mold sections are held between faces IS on rings l'I secured to the ends of the casing i5, so as to be capable of sliding in the radial direction thereon, while not being free to move in the axial direction. A pipe l8 .which is connected up by a quick release V coupling C to a flexible hose B enables fluid under pressure to be admitted under the control of v a valve D through the said hose from a source of fluid pressure to the space between the outer casing l5 and the extensible sleeve I4, for the purpose of pressing the mold sections I30, [31) together and enabling the mold to resist internal pressure. The arrangement employed for controlling the flow through the pipe I 8 consists of a valve D and a quick-release coupling 0 for enabling the pipe it to be disconnected from the flexible hose B connected to the source of" pressure fluid, for facilitating the removal of the mold casing and mold from the base It. The valve D- serves for maintaining the pressure in the space a, after the coupling C has been undone, until the mold has been transferred to the support upon which the 'molded article is left to harden, the said valve being closed before the coupling is undone.

The mold sections Ila, Ilb are further attached to threaded rods II passing through the outer casing II and coacting'with hand-wheels 20, for

' the purpose of displacing the mold sections in the radial direction. A sealing plate 2I is provided to close the space between the core and the mold at the upper end and is suitably shaped to mold the end of the pipe and is removably secured by dogs I". The outer surface of the lower end of the core is made of a suitable shape for forming a socket at the end of the pipe in conjunction with the lower end of the mold which is suitably shaped for molding the outside of the pipe.

sleeve 24 and an inner mold which is divided longitudinally into a number of segments 26. This inner mold is surrounded by an outer mold divided into three segments 21, which are held together by an extensible sleeve 28. There is a space 28 between the sleeve 28 and the outer casing 30. The outer mold segments 21 are displaceable by means of hand-wheels and screws as in the construction shown in Figure l.

The inner segments 2| fit against the outer segments 21 so that when the latter are forced together by hydraulic pressure applied in the space 2!, the inner segments are also forced The apparatus is used in the following manner:

' the space between the sleeve I and the mold sections Ila, Ilb is illled with concrete from the top, and the whole is vibrated to render the density of the concrete filling uniform. Then the sealing plate 2i is placed in position'and secured by means of the dogs I I1. Fluid under pressure is admitted to the space between the outer casing II and the sleeve I4 by operating the valve D, before or after filling with concrete, as required, so as to hold the mold sections IIa, lib together and enable them to resist internal pressure. Fluid under pressure is also admitted through the valve V and the inlet pipe II in the base and passes through the openings I2 in the end 2 of U the core Ia, so as to force the extensible sleeve 8 away from the core Ia, thereby compressing the concrete against the mold sections Ila, I lb and ensuring the formation of a very dense wall.

When the molding is completed, the pressure is released from the interior of the core by actuating the valve V to place the pipe II in communication with the atmosphere, allowing the extensible sleeve I to spring back against the outer surface of the core Ia, leaving a gap between the concrete pipe'and the sleeve 8. The sealing plate 2| is then removed. The casing II is then detached from the flange Iva and, with the mold sections Ita, Ilb and the pipe inside, is lifted irom the core Ia and base I0 and placed on a support which fits into the lower end of the pipe, the pipe sticking to the mold sections.

The pressure between the extensible sleeve I4 surrounding the mold sections I la, Itb and the outer casing I5 is then released by operating the valve D and the mold sections are drawn away from the pipe in the radial direction, sliding between the faces of the guide rings I'I against the pressure of the extensible sleeve, by rotating the hand-wheels 20 and thereby moving the threaded rods II outwardly, which are bolted to the mold sections Ila, Ilb. By this means it is possible to strip the mold from the pipe immediately after the molding without waiting for the pipe to set and harden. The casing I! together with the mold sections is then lifted oi! the pipe, and, after cleaning, the mold sections can be restored to the original shape by rotating the hand-wheels 20 in the reverse direction, whereupon the elasticity of the sleeve It draws the mold sections together again. Finally the mold is again placed over the core Ia, and secured to the flange Ila together, forming joints between them which are good enough to retain the plastic material while allowing air and water to escape into the cavities 32. When pressure is appliedinside the sleeve 24, the plastic material is compressed and any water it may contain is forced out through the Joints II into the cavities 32. It runs down these cavities, which extend over the whole length of the mold, and leaves the mold at the bottom end.- In other respectsthe construction and operation of this apparatus is similar to that described with reference to Figures 1-3.

Referring to the form shown in Figure 5, in order to enable a simpler shape pf core sleeve to be employed, the core sleeve 8, instead of extending down the outside of the part of the core which shapes the socket, as shown in Figure 2, is ofl'set inwardly at its lower end 38 where it is gripped between the lower conical end of the upper part of the core tube- 31 which is provided with a pressure chamber I and the conical internal recess 34' of the lower part 34 of the core, the two parts of the core being clamped together and to the base II by means of the inlet pipe II and the nut II', the upper end of the pipe II being screwed into the lower end I! of the part 21 of the core. An. annular piston 35 encircles the lower end of the part 34 of the core, the periphery of the said piston being a sliding fit inside an open ended cylinder 33 which is secured to the base It by means of screws It. U-leather packings 39 accommodated in recesses in the core part 34 and the cylinder 32, respectively, serve for sealing the piston 85. Fluid under pressure is supplied to the cylinder 23 below the piston 35 through a passage H to enable the piston to be raised to compress the socket portion of the pipe by means of a follower 40 which rests on the piston. The U-leather packings are held in position by means of supporting members It.

The apparatus shown in Figure 5 is used in the same manner as that shown in Figures 1 and 4, except thatin addition to admitting fluid under pressure through the pipe II, between the casing II and the sleeve I l and to the space 29, fluid under pressure is also admitted below the piston '8! to compress the socket part of the pipe on the to which is bolted an annular upper end portion I12 and a lower annular end portion Ill. The outer mold section III comprises three sesments which abut against the inner margins oi the end portions I12 and I13 and are located in their operative position shown in Figure 7 by means of annular ribs I18, I18 and I18, I88, respectively,

'- leaving'an annular space I18 between said mold section and the outer casing, into which the segments can be withdrawn to free the pipe by means of adjusting screws I8I and hand-wheels I82 having screw-threaded bores which are threaded on the screws I8I. An annular sealing ring I2I is inserted in the upper'end portion I12, being secured in position therein by means of dogs I" bolted to the end portion I12.

The core sleeve I8I is gripped at its lower end between a reduced conical part at the lower end of the tubular core part I31 and a corresponding conical opening in the bottom core part I38, the core parts I31 and I38 being clamped together and to the base I8I by means of a nut I38 screwed on to a threaded extension I48 oi the core part I31.

core part I31 and a conical cap I22 which is clamped to the core part I31 by means of a screw I23, the inner periphery of the sealing ring being conical and fitting closely around the cap I22.

The lower annular end portion "3 is bolted to an outer bottom mold member I32ior forming the socket of the pipe, said member having a flange I42 which abuts against a corresponding flange I43 on a cylinder I33 which is bolted to the base IIII and accommodates an annular piston I35 encircling the lower end of the bottom core part I38. U-leather packings I38 accommodated in recesses in the lower end of the core part N8 and in the cylinder I33, respectively serve for sealing the piston I35. The flanges I42 and I43 are tapered and are embraced by arcuate clamping members I44, which can be forced inwardly by means of hand-wheels I48 having threaded bores through which pass screw studs I45 bolted to the clamping members I44, said hand-wheels being rotatable in bearings I41 on At its upperend, the core sleeve I8I is gripped between the reduced tapered end of the asaasoa o! the mold section into the space I18 of the outer casing by rotation of the hand-wheels I82. I The above embodiments of the invention have been described indetail by way of example only, and it is to be understood that the invention is not restricted to the manufacture of pipes provided with sockets. The apparatus may be modifled as required. For example, the mold and core in the constructionsshown in Figures 2-5 need not be cylindrical, but may be of any suitable shape, and the mold may be divided into any desired number or sections.

'What I claim is:

1. An apparatus for molding hollow articles from or for lining hollow articles with plastic materials, comprising in combination, an outer ing and mold during the molding, a core on said base, an extensible covering sleeve surrounding brackets I48 bolted to the base IN. The piston I35 co-operates with a follower I48 in a similar manner to that of the follower shown in Figure 6, said follower being provided" with a number of radially extending lntemal protuberances I for engagement by the piston.

Fluid under pressure is admitted through the pipe II4 which passes upwardly through the interior of the core I31 and is bent'radially outwards, passing through the wall of the core so as to deliver the fluid between the core and the sleeve I8I Fluid under pressure is also admitted below the piston I 35 through the pipe I I2 for applying pressure to the plastic material in the the mold section together.

When the molding is completed, the nuts which hold down the dogs I'I'I are slackened and the sealing ring I2I is removed, after which the clamping members I44 are withdrawn from the flanges I42, I43 by rotation of the hand-wheels I48, thereby releasing the outer casing and allowing it to be lifted from the core and the base I8I together with the mold sections and the molded pipe which is subsequently released from the mold section I3I by withdrawing the segments said core and means for admitting fluid under pressure between the core and the coverin sleeve.

2. An apparatus ior molding hollow articles from or for lining hollow articleswith plastic materials, comprising the combination as set forth in claim 1, with an extensible covering sleeve surrounding the mold sections, means for introducing fluid under pressure between the outer casing and said covering sleeve during the molding, screw threaded rods connected to the mold sections and passed through the outer casing, and manual actuating means connected to said screw-threaded rods for retracting the mold sections after relaxation of the fluidpressure between the outer casing and the covering sleeve surrounding the mold.

3. An apparatus for molding hollow articles having a socket or for lining such hollow articles with plastic materials, comprising in combination, a mold having a socket-forming portion, a core comprising a lower part within the socketi'orrning portion of the mold and an upper part 1 having an extensible covering sleeve surrounding it, a movable mold member surrounding the ing said movable mold member in the axial direction of the mold to apply axial pressure to the socket of the hollow article during the molding.

4. An apparatus for molding hollow articles or lining hollow articles with plastic materials, comprising in combination, a mold having a socket-forming portion, a core comprising a lower part within said socket-forming portion of the mold and an upper portion having an extensible covering sleeve surrounding it, a movable mold member surrounding the lower part oi! the core and arranged to extend into the socketformin portion of the mold, a cylinder having a piston therein arranged to bear against said movable mold member, means for admitting fluid under pressure between the core and the covering sleeve so as to compress the plastic material, and means for admitting fluid under pressure to said cylinder tor actuating said piston to displace the movable mold member in the'axial direction of the mold to apply axial pressureto the socket oi. the hollow article during the. molding.

5. An apparatus for molding hollow articles or lining hollow articles with plastic materials, comprising in combination, a mold having a socket-iorming portion, a core comprising a lower part within said socket-forming portion of the mold and an upper part having anextensible covering sleeve surrounding it, a movable 'mold member surrounding the lower part or the core and arranged to extend into the socket-forming portion of the mold, an annular piston surround-( l5 ing the lower part of the core arranged to bear against said movable mold member, a cylinder for housing said piston, means for admitting fluid under pressure between the core and the covering sleeve so as to compress the plastic material, and means for admitting fluid under pressure to said cylinder for actuating said piston to displace the movable mold member in the axial direction 01' the mold to apply axial pressure to the socket or the hollow article during the molding.

6. An apparatus for molding hollow articles having a socket or for lining such hollow articles with plastic materials, comprising in combination, an outer casing, a mold comprising a plurality o! longit al sections and a sockettcrming portion, s d longitudinal sections being housed in said casinl. guide rings on said outer casing i'or preventing movement of said mold sections relatively to the outer casing in the axial direction, said guide rings permitting movement or the mold sections in the radial direction, a base -i'or supporting said outer casing and mold during the molding, a core on said base, an extensible covering sleeve surrounding said core, means for admitting fluid under pressure between the core and the covering sleeve so as to compress the plastic material, flanges on said base and socket-forming portion arranged to abut against one another, and means for releasably securing said flanges together, comprising radially adjustable clamping members capable of releasing the flangesLto enable the mold to be withdrawn from the core and base after relaxation of the fluid pressure between the core and the covering sleeve.

7.- An apparatus as set forth in claim 6, with means for adjusting the clamping members, comprising bearing supports on the base, screw studsrigid with the arcuate clamping members and manually adjustable members rotatable in' said bearing supports and having screw-threaded bores therein for radially adjusting the clam ing members.

ROBERT BRUCE REEVES. 

